1. Field of the Invention
The device relates to equipment used for air conditioning refrigerant recovery, recycling, evacuation, and/or recharge with particular use on commercial and automotive refrigerant containing systems.
2. Description of Related Art
Refrigerant Recovery, Recycling, Evacuation, and/or Recharge equipment (commonly referred to as R/R/R Equipment) is designed for use on Commercial and Automotive Refrigerant containing systems. Since it is illegal to vent CFC, HCFC and HFC refrigerants into the atmosphere, equipment has been developed to recover, extract, recycle, evacuate, flush, and/or recharge refrigerants such as R-12, R-22, R-134a and R-410a. The equipment comes in many forms.
R/R/R Equipment has been designed around components such as solenoid valves, check valves, compressors, vacuum pumps, oil separators, and filtration devices. The refrigerant flow through these devices are controlled by electro-mechanical or electronic controls. The following is a brief description on how these components are used in the R/R/R Equipment. Electro-Magnetic Solenoid valves are the current valve of choice to control the flow on R/R/R Equipment. Manufacturers add check valves (to prevent back flow), filters, and other preventive devices to protect solenoid valves used in their equipment.
The solenoid valves (SV) are designed with a small orifice, stem, tightly fitting plunger/core, and electrical coil. The small orifice in the SV is required to meet activation and non-activation pressure differential requirements. The tight spacing between the stem, coil and plunger/core are required for proper electro-magnetic operation. SV's are placed within the R/R/R Equipment plumbing circuit for the desired operation of each mode. This allows for flow control between recovery, recycle, evacuation, flush and/or recharge modes.
The physical design of a typical SV currently used in R/R/R Equipment incorporates a small orifice, plunge/core, spring, shell and electrical inductive coil. The smaller the orifice, the greater the holding power of the solenoid valve plunger/core. If the orifice diameter is too big, the plunger/core spring will not be strong enough to prevent back flow. Also note the electro-magnetic field may not be strong enough to open the plunger/core to the open position due to the differential operation pressures. The direct effect of the small orifice of the SV on the R/R/R Equipment is reduced flow rates during all operational modes.
Other problems associated with the SV are due to the presence of contaminants such as refrigerant system sealers, metal filings, chemical additives, oil, air, and moisture. Metal filings and other particles can lodge and jam between the tight space between the plunger/core and stem assembly making the SV inoperable. Refrigerant scaler, on the other hand, is in the liquid form until air/moisture makes direct contact with it. When the sealer activates, it will harden into a solid form. If the hardening takes place in the stem and plunger/core area, the SV will become inoperable. Excessive oil or liquid in the solenoid stem on the back side of the plunger can cause a delay or even prevent activation. This is called hydraulic lock. Another problem with the SV is that any contaminates on the surface of the orifice will cause the SV to not properly seal. The lack of the seal will cause internal leakage which will lead to overcharging, incomplete recovery, and loss of vacuum.
Compressors (CMP) are used to create a pressure differential during the recovery, recycling, flush and/or recharge operation. The CMP will suck refrigerant from one vessel and compress it into another vessel.
Vacuum Pumps (VP) are used to create a very low pressure area in a vessel during the evacuation mode. This is needed to remove (boil) any existing contaminates such as moisture and/or air before recharging. The presence of air and moisture will cause a refrigeration system to prematurely fail.
Oil separators and other filtration devices are placed in the R/R/R equipment plumbing circuit to meet recycling requirements.
Several attempts have been made to improve Refrigerant Recovery technology. For example, U.S. Pat. No. 5,479,788 issued to Roegner on Jan. 2, 1996 entitled “Refrigerant Recovery System” teaches a new refrigerant recovery system, but does not contemplate the recycling and evacuation of the refrigerant. The '788 patent contemplates the use of a ball valve for regulating flow of refrigerant as well as flare ball valves for service hoses, which are commonly found on solely recovery units. The '788 patent contemplates tank shut off ball valves that are required to disconnect a tank from the system. All of the ball valves in the '788 patent are only two-way valves.
U.S. Pat. No. 6,832,491 issued to Ramachandran et al. on Dec. 21, 2004 entitled “Compressor, Head, Internal Discriminator, External Discriminator, and Manifold Design for Refrigerant Recovery Apparatus” teaches the use of ball valves on the suction and discharge of a cylinder head in the recovery of refrigerant liquid and/or vapor. U.S. Pat. No. 6,779,350 issued to Ramachandran et al. on Aug. 24, 2004 entitled “Compressor Head, Internal Discriminator, External Discriminator, Manifold Design for Refrigerant Recovery Apparatus and Vacuum Sensor” teaches the same technology as the '491 patent. However, the type of ball valve contemplated by the '491 patent and '350 patent is a ball/spring valve, not a rotational ball valve. The spring holds a ball against a seat. When certain conditions occur, the ball will push against the spring allowing flow through. The ball is completely solid and has no holes. This structure is distinctly different from a rotational ball valve.
U.S. Pat. No. 6,371,440 issued to Genga et al. on Apr. 16, 2002 entitled “Electronic Motorized Zone Valve” teaches a valve actuator including a motor for changing the position of a valve, a switch for switching power to the motor, and a sensor for detecting the arrival of the valve at a desired position and for stopping the motor without using a mechanical stop. The ball valve contemplated in the '440 patent is for a two way ball valve which uses only one optical valve switch to estimate the valve position.
U.S. Pat. No. 5,875,638 issued to Tinsler on Mar. 2, 1999 entitled “Refrigerant Recovery System” teaches a system of refrigerant recovery very similar to that described in the '788 patent. The '638 patent is a refrigerant recovery only unit. The '638 patent contemplates the use of ball valves to connect hoses to removable tanks, manifolds, or the valves located on the removable tank. The '638 patent contemplates the use of solenoid valves for its normal operation. All of the valves mentioned in the '638 patent are two way valves.
U.S. Pat. No. 4,398,562 issued to Saarem et al. on Aug. 16, 1983 entitled “Motorized Diverter Valve” teaches a motor driven valve that diverts fluid flow from a single inlet port to either one of two outlet ports, or vice versa. The '562 patent teaches a three way valve that uses mechanical means to determine its position through Cams and micro-switches.
U.S. Pat. No. 5,099,867 issued to Emery on Mar. 31, 1992 entitled “Sealed Valve and Control Means Therefore” teaches a ball valve rotated by a spindle connected to a disc. The '867 patent covers a 2 way valve using magnetic pulse to determine the position. When the valve is moved, pulses are created.
U.S. Pat. No. 5,226,454 issued to Cabalfin on Jul. 13, 1993 entitled “DC Motor Actuated Flow Diversion Valve” teaches a three way valve using a DC motor, cam and micro switches to determine the position.
U.S. Pat. No. 4,299,251 issued to Dugas on Nov. 10, 1981 entitled “Optical Valve Position Sensing” teaches an apparatus for indicating the position of a rotary valve. The '251 patent covers a three light source light reflecting sensor to determine position of a valve. The light is reflected by mirrors to determine the position of the valve.
U.S. Pat. No. 6,843,070 issued to Suharno on Jan. 18, 2005 entitled “Refrigerant Recycling System With Single Ball Valve” teaches a system with a single manual ball valve can be used to connect a common port to either high or low service hoses. The flow through the system is controlled by solenoid valves.
U.S. Patent Application 2006/0070672 filed by Martins et al. entitled “Control Valve for an Engine Cooling Circuit” teaches a structure of a control valve for fluid circulation.
The desire remains for an automatic refrigerant recovery, recycler, recharging or evacuation equipment for the mobile air conditioning market.